This invention relates to a video recording and playback apparatus and method, and more particularly to a video recording and playback apparatus and method by which motion detection is performed.
A technique of displaying a video with an improved quality making use of an interpolation process of a video signal has been and is being popularized. The interpolation process of a video signal is performed based on a result of motion detection which is executed upon processing for production of a frame still picture free from blurring or upon format conversion of a video signal such as interlace to progressive conversion.
More particularly, for example, upon production of a frame still picture free from blurring, a difference between pixels at a corresponding position of different fields is calculated. Then, when the difference is equal to or greater than a predetermined threshold value, motion is detected, and the pixel is regarded as a moving pixel. On the contrary when the difference is smaller than the predetermined threshold value, motion is not detected, and the pixel is regarded as a still pixel. Further, for each pixel which is regarded as a moving pixel, an interpolation process is performed based on a pixel value of a preceding field, but any pixel which is regarded as a still pixel is outputted as it is. Through the process, a still picture of a high picture quality free from blurring is obtained.
The method described above, however, is disadvantageous in that, if a video signal inputted includes weak electric field noise, CCD (Charge Coupled Device) noise of a camera or noise generated through compression and decompression processes of the MPEG (Moving Picture Experts Group) system or the like, then the noise is detected as motion in error upon motion detection.
Also it has been proposed to perform a spatial filter process prior to motion detection so that such noise may not be detected as motion in error. However, the spatial filter process suppresses not only noise components but also motion components of the signal. Consequently, the proposed solution is disadvantageous in that motion which should originally be detected is not detected.